Boats??
Little tinnies are ok, but if you want anything bigger, the advice I got was "stand under a cold shower and tear up fifty dollar bills. It's much the same, and it's cheaper"
If you go to any capital city you will be able to find millions of dollars worth of "yachts" tied up at expensive moorings, growing barnacles. Sometimes they go sailing.
In the capital cities many of the aeroplanes are the same. GA may be dying in the cities. Many were never viable, like the yachts. They got a big boost decades ago when our government gave huge tax concessions on aircraft purchases (probably to aid in oil search) so all the tax dodgers bought an aeroplane, and the salespeople organised a charter licence for them. Fortunes were made selling aeroplanes to fools, and teaching other fools to fly them. (yes I was one of the fools.) It got quite frantic but soon the mining fever died down and things slowed. The aircraft makers expected every Tom Dick and Harry to buy an aeroplane and they flooded the country with two seat trainers. But Tom, Dick and Harry did not buy and the industry slowed down. The factories slowed, and some stopped, blaming insurance costs.
So we have lots of under utilised aeroplanes that have been poorly maintained. Some have flown lots of hours. Some have not. Many are sound airframes that need a new engine and some TLC. Some need major work.
GA will never die completely because we live in a huge country with lots of still undiscovered minerals and poor transport. Smart people will want to go out there and look. It is also the only sensible way to provide essentiall services for those who live out there. Boeings can't do it.